NSFW Communities Showing as Empty, Despite Still Populating in Instance View?

I'm not sure if this is a Sync thing, something I have configured improperly in my settings, or if there is just something happening at the Lemmy level that I don't understand given the complexity of instances, federation, etc.

When I attempt to view a NSFW community I get a message that it has no posts. However, if I view the instance as a whole posts from various communities are visible, so there is definitely content that exists. I've tried this with a few instances and it seems to only occur with NSFW communities.

For example, If I go the the "Instance" view for Lemmy.NSFW I can see various posts, but if I open a specific community on the instance (directly or through a post) it says it's empty. The same issues does not seem to occur with other SFW instances or communities.

Bug? Or is this something built into Lemmy that I've misunderstood / a setting in Sync that I've overlooked?